Automatic lubrication means for universal joints are not new. Representative of the prior art are the patents to Kayser, U.S. Pat. No. 3,006,168, dated Oct. 31, 1961 and Delker, U.S. Pat. No. 3,326,323, dated June 20, 1967. These inventions both require specially constructed drive shafts with lubricant reservoirs in the drive shaft itself.
Each company manufacturing trucks and commercial vehicles designs its own drive shaft along with body style and all other facets of the vehicle. Thus, drive shafts are not standard as to length or diameter and to have an automatic lubrication system according to the prior art, one would have to have enumerable sizes and lengths of drive shaft especially constructed to replace existing equipment. As will be clear to those in the commercial vehicle industry, the replacement and labor costs are prohibitive.
What is needed is an independently mountable lubrication system which is universally applicable to the drive shafts of all commercial vehicles. The invention described herein is just such a device.
Heretofore, it was recognized that a great deal of difficulty is encountered in trying to lubricate a rotating joint, in that, the conduits conducting the lubricant must rotate simultaneously with the joint or else the lubrication can be achieved only during the times of complete stoppage of the joint. Hand operated lubrication by a grease gun is common.